Circumferential stabilization with ghost screwing after posterior resection of spinal metastases via transpedicular route

Abstract

Various surgical methods have been described for treating spinal metastases, namely, en bloc spondylectomy, minimally invasive techniques, and anterior and posterior approaches. The main goals in surgical intervention for these lesions are tumor removal and establishment of strong, durable stabilization. The least invasive method is always preferred. Posterior transpedicular spondylectomy meets all these needs, as this method achieves tumor excision and stabilization of the anterior and posterior spine through one posterior incision and in the same surgical session. The surgeon circumferentially excises a spinal metastasis and then achieves circumferential stabilization in the same session. Numerous circumferential stabilization methods have been used to date, including placement of free bone grafts or cages or acrylic grafts, or insertion of an acrylic graft supported by a Steinmann pin anteriorly and by posterior transpedicular fixators or a Luque rectangle posteriorly. This article describes seven cases of spinal metastasis in which an alternative circumferential stabilization technique known as "ghost screwing" was performed. The first step in this method is circumferential decompression, achieved with laminectomy followed by eggshell corpectomy via the transpedicular route. Then a short segmental transpedicular stabilization system is fixed to the vertebrae cranial and caudal to the laminectomy/corpectomy defect. Prior to fixing the rods in place, an additional screw is mounted on each rod such that the screw shaft protrudes into the defect space. Once the rods are fixed and the two extra screws are optimally positioned, acrylic bone cement is introduced into the defect site, encasing the ghost screws and forming an anterior graft upon hardening. The outcomes in our cases were excellent. All seven patients had uneventful postoperative periods and all experienced pain relief and were able to mobilize early. Direct connection of the anterior acrylic graft to the posterior fixation system via ghost screws makes this system strong and durable, and prevents subsidence or horizontal displacement of the graft. Such complications can be serious issues with other circumferential systems that use independent anterior and posterior fixators.

Posterior approaches for symptomatic metastatic spinal cord compression

“…There were 3 prospective cohort trials 32,33,38 and 11 retrospective case series. 4,5,[8][9][10]12,13,18,20,30,34 Class I evidence reporting on the use of PTAs was not available from any of the selected articles.…”

“…Bilsky et al 18 (8 patients) evaluated single-stage PTA for circumferential epidural decompression and 3-column stabilization using a titanium cage for upper thoracic spine neoplastic disease and reported one neurological outcome (I/M Frankel grades 100%). Senel et al 30 (7 patients) evaluated circumferential stabilization with ghost screwing (that is, the creation of an acrylic anterior graft that is directly connected to the posterior transpedicular stabilizing system via 2 ghost screws) after posterior resection of spinal metastases via a transpedicular route. They reported that neurological function remained unchanged for all patients not lost to follow-up.…”

“…Two of the prospective studies reported outcomes: Street et al noted that 75% of patients were alive at 6 months, 32 and Wang et al noted an overall median survival of 7.7 months. 33 Seven of the 11 retrospective studies reported survival outcomes as overall median survival time (11.3 months, 9 9.75 months, 4 8.9 months, 10 8.8 months 8 ), survival at the 12-month follow-up (43%, 30 37.5% 12 ), and survival at 6 months (88.9%). 5 Only 9 of the 14 studies reported RRs.…”

“…In all 3 prospective studies, the outcome measured was pain relief (100% 32,38 and 96% 33 ). Eight of the 11 retrospective studies reported pain relief (100%, 4,5,13,30,34 95.2%, 10 88%, 18 and 62.5%…”

“…Authors in all 14 studies reported performing a PTA based on the location of the tumor and the surgeon's familiarity with the approach and reconstructive options. 4,5,[8][9][10]12,13,18,20,30,[32][33][34]38 A posterior transpedicular approach with instrumentation was used in 7 studies to stabilize the spine. 4,5,10,18,20,30,33 Deutsch et al reported that a PTA was also used over an anterior approach owing to age, comorbidities, and limited life expectancies.…”